1. Field of the Invention
The present invention relates to a semiconductor device having a package structure, a method of manufacturing the same and a method of measuring a position of the semiconductor device, and particularly to a semiconductor device capable of enhancing the accuracy of measurement of a position of the semiconductor device, which is executed after the surface of an sealing resin (mold) for the semiconductor device is placed over a mounting board with being opposed thereto, a manufacturing method thereof and a method of measuring the position of the semiconductor device.
This application is counterpart of Japanese patent applications, Serial Number 117317/2002, filed Apr. 19, 2002, the subject matter of which is incorporated herein by reference.
2. Description of the Related Art
For example, Japanese Laid-Open Patent No. 2001-196403 has disclosed a semiconductor device having a WCSP (abbreviation for Wafer Level Chip Size Package or Wafer Level Chip Scale Package) structure which allows electrode terminals to protrude above an sealing resin for the semiconductor device. Since a WCSP technology performs packaging in a state of a semiconductor wafer formed with circuit patterns as it is, each of semiconductor chips (pieces) separated by dicing results in a semiconductor device. A package size substantially identical to a chip size can be realized.
As shown in FIG. 15, a semiconductor device 500 having a WCSP structure is placed over a mounting board 600 with a back 502 of a semiconductor substrate 501 being turned up and a surface 504 of an sealing resin 503 and electrode terminals 505 being opposed to the mounting board 600. Thereafter, an opto-mechanical process is performed in which the intensity of light L2 or L3 returned when laser light L1 is applied to a semiconductor device 500 or a mounting board 600 is measured. A position where a change in the intensity of the returned light L2 or L3 is detected, is regarded as an end (outer peripheral position or contour) 506 of the semiconductor device 500, and a position to mount the semiconductor device 500 is measured. If a distance (e.g., measured value P1 in FIG. 15) from a reference point falls within a defined range, it can be then judged that the electrode terminals 505 of the semiconductor device 500 have suitably been connected to their corresponding electrode terminals 601 of the mounting board 600 as shown in FIG. 15. If a distance (e.g., measured value P2 in FIG. 16) from the reference point falls outside the defined range, it can be then judged that the electrode terminals 505 of the semiconductor device 500 have not suitably been connected to their corresponding electrode terminals 601 of the mounting board 600 as shown in FIG. 16 by way of example.
In the above-described conventional semiconductor device 500, however, the back 502 of the silicon substrate 501 is finished to a mirror surface by a grinding process to thin the thickness of the silicon substrate 501. Hence the difference between the intensity of the returned light L3 reflected by the back 502 of the semiconductor device 500 and the intensity of the returned light L2 reflected by the mounting board 600 is small. Therefore, a problem arises in that the frequency of making it unable to detect the end 506 of the semiconductor device 500 or misjudging each point other than the end 506 as an end increases and the accuracy of a position measurement in a process of inspecting a mounted state of each semiconductor device at its manufacturing stage is reduced.